The present invention relates to a process for bonding wallpapers to wall insulating boards or films made of a foamed polymer, and to the resulting composite sheeting which may be used as a wall covering.
Wall insulating boards or films, in particular those of foamed polystyrene, are commonly known and are used for covering walls prior to pasting on the wallpaper. Such insulating boards are available as folded and unfolded boards or as film rolls. In general, their spatial form is rectangular, with their thickness being very small in comparison to their width and length. With the aid of these boards and films it is possible, e.g., to cover wall cracks, to achieve a certain thermal insulation and to prevent the deposit of moisture.
A certain disadvantage of wall insulating boards or films of this kind may arise from the fact that, in case of the action of extremely high temperatures, caused, e.g., by flames, the typically thermoplastic polymer begins to melt and/or its foam structure starts to break down, even before the flamepoint of the wallpaper pasted on it is reached. Thus a cavity is produced between the wallpaper and the wall, which contributes to a rapid burning up of the wallpaper as soon as its flamepoint is reached. In order to eliminate this disadvantage, it is known to render fireproof either the wall insulating board or film, or the wallpaper, or both. In many cases this special measure is not required, however, so that the manufacture of these products becomes unnecessarily complicated and expensive.